Vehicles using fossil fuel, such as gasoline and diesel oil, create exhaust gases which generally include various pollutants. A technology of using storage or secondary batteries, which can be charged and discharged, as a power source for vehicles has attracted considerable attention as one method of solving the above-mentioned problem. As a result, electric vehicles (EV), which are operated using only a battery, and hybrid electric vehicles (HEV), which jointly use a battery and a conventional combustion engine, have been developed, and some are now being used commercially. Various nickel-metal hydride (NIMH) secondary batteries have been widely used as the power source in EV and HEV applications. More recently, however, the use of lithium-ion, particularly lithium-polymer, secondary batteries has been proposed.
High output and large capacity are needed for such secondary batteries to be used as the power source. For this reason, such batteries are typically constructed from a plurality of smaller battery cells (unit cells) that are interconnected in series or in parallel with each other to form a battery module. A plurality of battery modules is interconnected to obtain a battery pack having the desired output and capacity characteristics.
In order to use battery packs of the type described above in various applications, including applications where the devices which are in power communication with the battery pack are subject to movement, such as, for example, various motorized vehicles, aircraft, watercraft, trains and the like, it is generally desirable to establish durable battery cell interconnects which may be used to electrically interconnect a plurality of cells within an individual battery module, or between battery modules, or both, and to provide electrical interconnects between modules to form the battery pack. Durable battery cell interconnects must provide suitable electrical interconnections and electrical contacts in the manufacturing and operational environments, which can include various forces and moments associated with installation or movement of the vehicle or craft, as well as temperature extremes and atmospheric contaminants that can induce various forms of corrosion and other degradation processes. While some interconnects for interconnecting individual battery cells have been proposed, the nature of the battery cell electrodes, such as their size, shape, spacing, electrode materials, material characteristics and the like, as well the nature of the battery cells, such as their size, shape, cell spacing, intra-cell and inter-cell electrode spacing and the like, is constantly and rapidly changing as new battery cell configurations and materials are developed. Therefore, it is desirable to develop interconnects for battery cells that may be used in battery modules and battery packs of the types described above.